GanttProject is a cross-platform desktop tool for project scheduling and management. It runs on Windows, Linux and MacOSX, it is free and its code is opensource.

What can it do?
* Gantt chart. - Create work breakdown structure, draw dependencies, define milestones.
* Resources. - Assign human resources to work on tasks, see their allocation on the Resource Load chart.
* PERT chart. - Generate PERT chart from Gantt chart.
* Export. - Save charts as PNG images, generate PDF and HTML reports.
* Interoperate. - Import projects from and export them to Microsoft Project formats. Export to spreadsheets with CSV.
* Collaborate. - Share projects with your colleagues using WebDAV.